function geturl() {

var allcookies = opener.document.cookie;
var pos_url = allcookies.indexOf("url=");
if(pos_url != -1) {
	alert("cookie exists"); 
	var start = pos_url + 4;
	var end = allcookies.indexOf(";", start);
	if(end == -1) end = allcookies.length;
	var value = allcookies.substring(start, end);
	value = unescape(value);
	var url = "http://silo.cs.indiana.edu:13795/rate_down.html?urlval=" + value;
	alert("Url: " + url);
	var framesrc = document.getElementById("iframe");
	framesrc.setAttribute("src", url);
}
else alert("cookies don't exist");

}